Asymmetric Capability Coordination in Dual Connectivity

1. A method comprising: sending from a master radio access node to a secondary radio access node an addition request message comprising configuration information enabling the secondary radio access node to operate with the master node for dual connectivity with a user equipment, wherein the addition request message indicates a first version number associated with the configuration information; receiving at the master radio access node from the secondary radio access node, in reply to the addition request message, a request acknowledgement message acknowledging participation by the secondary radio access node in the dual connectivity, wherein the request acknowledgement message indicates a second version number associated with a configuration of the secondary radio access node; determining, using the first version number and the second version number, dual connectivity coordination capabilities between the master radio access node and the secondary radio access node and a configuration of the user equipment for the dual connectivity, wherein the determining comprises that the secondary radio access node does not comprehend a newer version radio access technology for the dual connectivity; and thereafter the master radio access node participating in the dual connectivity when communicating wirelessly with the user equipment, wherein: the dual connectivity comprises, based on the determining, the master radio access node communicating wirelessly with the user equipment using the newer version radio access technology and the secondary radio access node communicating wirelessly with the user equipment using an older version radio access technology, and the addition request message and the request acknowledgement message are in accordance with radio resource control signaling of the older version radio access technology, wherein based at least on the determining using the first version number and the second version number the master radio access node is comprehending both the newer version radio access technology and the older version radio access technology for the communicating.

2. The method according to claim 1 , wherein the older version radio access technology is E-UTRAN and the newer version radio access technology is 5G.

3. The method according to claim 1 , wherein the request acknowledgement message indicates a configuration of the secondary radio access node for participating in the dual connectivity.

4. The method according to claim 1 , wherein: the first version number is valid for at least a portion of the configuration information; and the first version number and the second version number are used to define which of the master radio access node or the secondary radio access node performs comprehending of both the newer version radio access technology and the older version radio access technology.

5. The method according to claim 1 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the older version radio access technology and the secondary radio access node communicating with the user equipment using the newer version radio access technology; and the configuration information in the addition request message comprises a configuration of a master cell group of which the master radio access node is a member, and capabilities of the user equipment with regard to the newer version radio access technology.

6. The method according to claim 1 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the newer version radio access technology and the secondary radio access node communicating with the user equipment using the older version radio access technology; and the configuration information in the addition request message comprises a reference configuration for the secondary radio access node, and capabilities of the user equipment with regard to the older version radio access technology.

7. A computer readable memory storing computer program instructions that, when executed by one or more processors, cause the master radio access node to perform the method according to claim 1 .

8. An apparatus comprising: at least one processor; and at least one memory storing computer readable instructions that when executed by the at least one processor cause the apparatus to perform actions comprising: sending from a master radio access node to a secondary radio access node an addition request message comprising configuration information enabling the secondary radio access node to operate with the master node for dual connectivity with a user equipment, wherein the addition request message indicates a first version number associated with the configuration information; receiving at the master radio access node from the secondary radio access node, in reply to the addition request message, a request acknowledgement message acknowledging participation by the secondary radio access node in the dual connectivity, wherein the request acknowledgement message indicates a second version number associated with a configuration of the secondary radio access node; determining, using the first version number and the second version number, dual connectivity coordination capabilities between the master radio access node and the secondary radio access node and a configuration of the user equipment for the dual connectivity, wherein the determining comprises that the secondary radio access node does not comprehend a newer version radio access technology for the dual connectivity; and thereafter: the master radio access node participating in the dual connectivity when communicating wirelessly with the user equipment, wherein: the dual connectivity comprises, based on the determining, the master radio access node communicating wirelessly with the user equipment using one of an older version radio access technology or the newer version radio access technology and the secondary radio access node communicating wirelessly with the user equipment using the older version radio access technology; and the addition request message and the request acknowledgement message are in accordance with radio resource control signaling of the older version radio access technology, wherein based at least on the determining, the first version number and the second version number of the radio access technology the master radio access node is comprehending both the newer version radio access technology and the older version radio access technology for the communicating.

9. The apparatus according to claim 8 , wherein the older version radio access technology is E-UTRAN and the newer version radio access technology is 5G.

10. The apparatus according to claim 8 , wherein the request acknowledgement message indicates a configuration of the secondary radio access node for participating in the dual connectivity.

11. The apparatus according to claim 8 , wherein: the first version number is valid for at least a portion of the configuration information; and the first version number and the second version number are used to define which of the master radio access node or the secondary radio access node performs comprehending of both the newer version radio access technology and the older version radio access technology.

12. The apparatus according to claim 8 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the older version radio access technology and the secondary radio access node communicating with the user equipment using the newer version radio access technology; and the configuration information in the addition request message comprises a configuration of a master cell group of which the master radio access node is a member, and capabilities of the user equipment with regard to the newer version radio access technology.

13. The apparatus according to claim 8 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the newer version radio access technology and the secondary radio access node communicating with the user equipment using the older version radio access technology; and the configuration information in the addition request message comprises a reference configuration for the secondary radio access node, and capabilities of the user equipment with regard to the older version radio access technology.

14. The apparatus according to claim 8 , wherein the apparatus is the master radio access node or a portion thereof.

15. A method comprising: receiving at a secondary radio access node from a master radio access node an addition request message comprising configuration information enabling the secondary node to operate with the master node for dual connectivity with a user equipment, wherein the addition request message indicates a first version number associated with the configuration information; sending from the secondary radio access node to the master radio access node, in reply to the addition request message, a request acknowledgement message acknowledging participation by the secondary radio access node in the dual connectivity, wherein the request acknowledgement message indicates a second version number associated with a configuration of the secondary radio access node, and wherein the first version number and the second version number are for use in determining dual connectivity coordination capabilities between the master radio access node and the secondary radio access node and a configuration of the user equipment for the dual connectivity, wherein the determining comprises that the secondary radio access node does not comprehend a newer version radio access technology for the dual connectivity; and thereafter the secondary radio access node establishing an active communication link with the user equipment for the dual connectivity, wherein: the dual connectivity comprises, based on the determining, the master radio access node communicating wirelessly with the user equipment using one of an older version radio access technology or the newer version radio access technology and the secondary radio access node communicating wirelessly with the user equipment using the older version radio access technology; and the addition request message and the request acknowledgement message are in accordance with radio resource control signaling of the older version radio access technology wherein based at least on the determining, the first version number and the second version number version radio access technology the second radio access node is comprehending only the older version of the radio access technology for the communicating.

16. The method according to claim 15 , wherein: the older version radio access technology is E-UTRAN and the newer version radio access technology is 5G; and the request acknowledgement message indicates a configuration of the secondary radio access node for participating in the dual connectivity.

17. The method according to claim 15 , wherein: the first version number is valid for at least a portion of the configuration information; and the first version number and the second version number are for use to define which of the master radio access node or the secondary radio access node performs comprehending of both the newer version radio access technology and the older version radio access technology.

18. The method according to claim 15 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the older version radio access technology and the secondary radio access node communicating with the user equipment using the newer version radio access technology; and the configuration information in the addition request message comprises a configuration of a master cell group of which the master radio access node is a member, and capabilities of the user equipment with regard to the newer version radio access technology.

19. The method according to claim 15 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the newer version radio access technology and the secondary radio access node communicating with the user equipment using the older version radio access technology; and the configuration information in the addition request message comprises a reference configuration for the secondary radio access node, and capabilities of the user equipment with regard to the older version radio access technology.

20. A computer readable memory storing computer program instructions that, when executed by one or more processors, cause the secondary radio access node to perform the method according to claim 15 .

21. An apparatus comprising: at least one processor; and at least one memory storing computer readable instructions that when executed by the at least one processor cause the apparatus to perform actions comprising: receiving at a secondary radio access node from a master radio access node an addition request message comprising configuration information enabling the secondary node to operate with the master node for dual connectivity with a user equipment, wherein the addition request message indicates a first version number associated with the configuration information; sending from the secondary radio access node to the master radio access node, in reply to the addition request message, a request acknowledgement message acknowledging participation by the secondary radio access node in the dual connectivity, wherein the request acknowledgement message indicates a second version number associated with a configuration of the secondary radio access node, and wherein the first version number and the second version number are for use in determining dual connectivity coordination capabilities between the master radio access node and the secondary radio access node and a configuration o f the user equipment for the dual connectivity, wherein the determining comprises that the secondary radio access node does not comprehend a newer version radio access technology for the dual connectivity; and thereafter the secondary radio access node establishing an active communication link with the user equipment for the dual connectivity, wherein: the dual connectivity comprises, based on the determining, the master radio access node communicating wirelessly with the user equipment using both an older version radio access technology or the newer version radio access technology (RAT) and the secondary radio access node communicating wirelessly with the user equipment using the older or the newer version radio access technology; and the addition request message and the request acknowledgement message are in accordance with radio resource control signaling of the older version radio access technology wherein based at least on the determining using the first version number and the second version number version radio access technology the second radio access node is comprehending only the older version of the radio access technology for the communicating.

22. The apparatus according to claim 21 , wherein: the older version radio access technology is E-UTRAN and the newer version radio access technology is 5G; and the request acknowledgement message indicates a configuration of the secondary radio access node for participating in the dual connectivity.

23. The apparatus according to claim 21 , wherein: the first version number is valid for at least a portion of the configuration information; and the first version number and the second version number are for use to define which of the master radio access node or the secondary radio access node performs comprehending of both the newer version radio access technology and the older version radio access technology.

24. The apparatus according to claim 21 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the older version radio access technology and the secondary radio access node communicating with the user equipment using the newer version radio access technology; and the configuration information in the addition request message comprises a configuration of a master cell group of which the master radio access node is a member, and capabilities of the user equipment with regard to the newer version radio access technology.

25. The apparatus according to claim 21 , wherein: the dual connectivity comprises the master radio access node communicating with the user equipment using the newer version radio access technology and the secondary radio access node communicating with the user equipment using the older version radio access technology; and the configuration information in the addition request message comprises a reference configuration for the secondary radio access node, and capabilities of the user equipment with regard to the older version radio access technology.

26. The apparatus according to claim 21 , wherein the apparatus is the secondary radio access node or a portion thereof.